Technologicalimprovements and reduced equipment costs have made converting solar energydirectly into electricity far more cost-efficient in the last decade. However, the threshold of economic viabilityfor solar power (that is, the price per barrel to which oil would have to risein order for new solar power plants to be more economical than new oil-firedpower plants) is unchanged at thirty-five dollars.
Whichof the following, if true, does most to help explain why the increasedcost-efficiency of solar power has not decreased its threshold of economicviability?
A.The cost of oil has fallen dramatically.
B.The reduction in the cost of solar-power equipment has occurred despiteincreased raw material costs for that equipment.
C.Technological changes have increased the efficiency of oil-fired power plants.
D.Most electricity is generated by coal-fired or nuclear, rather than oil-fired,power plants.
E.When the price of oil increases, reserves of oil not previously worthexploiting become economically viable.
